Install libpam-cgfs by entering the following commands in the terminal:
sudo apt update sudo apt install libpam-cgfs
PAM module for managing cgroups for LXC
Containers are insulated areas inside a system, which have their own namespace for filesystem, network, PID, IPC, CPU and memory allocation and which can be created using the Control Group and Namespace features included in the Linux kernel. . This provides a Pluggable Authentication Module (PAM) to provide logged-in users with a set of cgroups which they can administer. This allows for instance unprivileged containers, and session management using cgroup process tracking.